The invention relates to a blood serum applicator for use in cataphoretic apparatus, and more particularly, to such applicator which may be used to apply a sample of blood serum to a serum bearing member.
As is well recognized, an automatic cataphoretic apparatus is arranged to perform the supply of a serum bearing member, the application of a serum thereto, a cataphoretic process, the steps of dyeing, decolorizing and drying, photometry and recording in a sequential and automatic manner (see pending U.S. patent application Ser. No. 829,957 and German patent application No. P 27 40 073.3). Specifically, a roller which wets a serum bearing member with a buffer solution feeds it into a serum application station where a blood serum to be examined is applied to the bearing member, which is then supplied into a cataphoresis vessel. A cataphoretic process takes place within the vessel, and after the completion of the cataphoretic process, the bearing member is transferred into a dyeing vessel where the steps of dyeing, decolorizing and drying take place. The dried bearing member is subject to photometry with a densitometer. The data obtained by the photometry is recorded by means of a recorder.
A blood serum bearing member comprises a sheet of cellulose acetate to which blood serum is applied with a penpoint application in a rectilinear form of a given narrow width. The serum is then electrically energized to obtain a fractionated pattern of the serum.
A conventional serum application is illustrated in FIGS. 1 and 2. Referring to these Figures, the serum applicator comprises a plurality of serum application members 3 which are carried by a support arm 4 in juxtaposition. The member 3 includes a plate-shaped penpoint 1 having an applying surface 1a which is attached to a support shank 2. The support shank 2 fixedly carries a pin 5 which is fitted in a slot 4a formed in the support arm 4, thereby allowing a limited vertical movement of the penpoint as permitted by the vertical extent of the slot. In use, the support arm 4 is lowered to immerse the penpoint 1 of the individual application members 3 into a supply of blood serum. After the serum is applied to the surface 1a of the penpoints, the support arm 4 is raised and moved to a location over a blood serum bearing member 6 where it is lowered to move the application members 3 down so that the surfaces 1a may be brought into contact with the bearing member 6, thus applying the serum to the latter.
However, the described construction of the serum application results in a disadvantage that the serum is deposited on the bearing member in a deformed form, as illustrated in FIGS. 3(C) and (D). Specifically, the support arm 4 is channel-shaped so as to have a pair of limbs 4d, 4e which are formed with openings 4b, 4c extending therethrough for allowing the shank 2 to pass therethrough. It is difficult to achieve a high accuracy in the size and location of openings 4b, 4c. If the vertically spaced openings are misaligned or if there is any clearance between the edge of the openings and the shank 2, the application member 3 will assume a slanted or inclined position. If such an application member is directly used in the application of the blood serum to the bearing member, the surface 1a of the penpoint 1 will be inclined when abutting against the bearing member 6, as illustrated in FIGS. 3(A) and (B). As a consequence, the deposition of serum 20 will be offset to one side, as illustrated in FIGS. 3(C) and (D). Another difficulty is that of achieving a high accuracy in the manufacturing of the pin 5 and its engagement with the slot 4a. If the pin 5 extends in a wrong direction or if there is a clearance between the pin and the slot 4a, the applying surfaces 1a of the individual pin point 1 will not be aligned with each other on the bearing member 6 but will be staggered thereon, with the result that the applied samples of serum will be similarly staggered when they are subject to a cataphoretic process, which is undesirable.